[$] Code tagging and memory-allocation profiling

The code-tagging mechanism proposed lastyear by Suren Baghdasaryan and Kent Overstreet has been the subject of anumber of (sometimes tense) discussions. That conversation came to thememory-management track at the 2023 LinuxStorage, Filesystem, Memory-Management and BPF Summit, where itsdevelopers (Baghdasaryan attending in-person and Overstreet remotely) triedto convince the attendees that its benefits justify its cost.